The present invention relates to a system for lifting mud flaps into a raised position away from the surface of the truck tires, and in particular, to a pneumatic power system for raising the mud flaps of a truck when the truck is backing up in order to prevent damage to the mud flaps.
Mud flaps are mounted on trucks and trailers to prevent the tires of such vehicles from spraying water, mud and other road debris. The mud flaps also prevent damage to the body of the truck or trailer caused by stones and similar hard objects. One of the primary benefits of mud flaps is to prevent the water spray and debris discharge onto the vehicles in proximity to such truck or trailer as the vehicles travel down the road.
A majority of states have statutes or regulations which require trucks and trailers to be furnished with mud flaps. The spacing between the bottom edge of the mud flap and the ground and the spacing between the inner surface of the mud flap and the vehicle tires are typically regulated by the states. The fines and other penalties for operating a vehicle without proper mud flaps are a nuisance and can be a significant expense and legal risk for repeat violations.
Vehicles which require mud flaps, such as trucks and trailers, frequently have mud flaps torn from their mounting brackets during normal operation of the vehicle. The majority of the mud flaps are torn off when the vehicle is backing up or when dumping a load at the back of the vehicle. Trucks used in construction and paving operations often lose a mud flap. In paving operations, a dump truck with a load of asphalt will back up to a paving machine and will dump its load while the paving machine is pushing the dump truck forward. The tires of the truck or the front of the paving machine will frequently catch the end of the mud flap and rip the flap right out of its bracket.
When trucks or trailers are backing up over rough terrain, such as stone, loose dirt, heavy snow/ice, curbs, or other similar obstacles, the mud flaps are often caught under the tires of the vehicle, which tears the mud flap right out of the mounting bracket. In some cases, the weight of the vehicle backing over the mud flap will pull the flap brackets, chrome, and other mounting devices, from the vehicle.
Owners and operators of vehicles which require mud flaps are frustrated by the time and expense required to replace mud flaps. The mud flaps themselves are not very expensive, but the lost operating time for the vehicle and the additional manpower expense required to install new mud flaps can become a significant operating expense.
In the prior art, U.S. Pat. No. 3,877,722 (Conner) shows a vertical center bar fastened to the mud flap. The mud flap is supported by the center bar in operation, but is detached from the center bar to permit the roll up of the mud flap when not in use. The center bar is pivoted to a parallel position with the frame.
U.S. Pat. No. 4,319,764 (Whitaker) describes the problems in the logging industry with damage to the mud flaps when backing up over rough terrain and obstacles. Whitaker approaches the problem by designing a special frame to hold the mud flaps in place relative to the wheel. The horizontal swing arms of the mounting frame are pivotably mounted to permit the arm to swing forward to minimize damage as the vehicle is backing up. A positive stop or blocking means is used to prevent the swing arms from swinging in a rearward direction, which permits normal use of the mud flap as the vehicle is traveling down the highway.
A two part mud flap with a lower screen which is pivotably mounted to the upper portion of the mud flap is disclosed in U.S. Pat. No. 4,362,310 (Goodall). The linkages mounted on the frame permit the lower screen to pivot in either direction when obstruction is encountered.
U.S. Pat. No. 4,964,655 (Tucker) provides a number of rubber discs connect together with metal segments that allow movement of the mud flap in only one direction. The rubber discs rotate on metal rods. The rubber discs rotate when on obstruction is encountered such that the rubber discs rotate to prevent the mud flap from snagging against a tire or other object.
U.S. Pat. No. 3,248,126 (Saxton et al.) and U.S. Pat. No. 3,582,109 (Moore) disclose relatively devices for raising the mud flaps of a dump truck having an underbody on which a power cylinder is mounted. In each case, the power cylinder is connected to a lever arm, which is in turn connected to a cable secured to the mud flaps. Each of these devices, however, is relatively complex, requires the vehicle to have a suitable underbody on which to secure the components, and leaves the components unprotected from the environment.
Owners and operators of vehicles with mud flaps have a need for a device which can reduce the likelihood of tearing off a mud flap when backing up the vehicle or when dumping a load. The device must be relatively inexpensive and be easy to install and operate on existing vehicles.